WIP: Collapse Splicer and SplicerKind

crate_universe/extensions.bzl

@@ -628,6 +628,9 @@ def _generate_hub_and_spokes(
         splicing_manifest = splicing_manifest,
     )
 
+    # The workspace root when one is explicitly provided.
+    nonhermetic_root_bazel_workspace_dir = module_ctx.path(Label("@@//:MODULE.bazel")).dirname
+
     # If re-pinning is enabled, gather additional inputs for the generator
     kwargs = dict()
     if repin:
@@ -658,8 +661,10 @@ def _generate_hub_and_spokes(
             "metadata": splice_outputs.metadata,
         })
 
-    # The workspace root when one is explicitly provided.
-    nonhermetic_root_bazel_workspace_dir = module_ctx.path(Label("@@//:MODULE.bazel")).dirname
+        for path_to_track in splice_outputs.extra_paths_to_track:
+            # We can only watch paths in our workspace.
+            if path_to_track.startswith(str(nonhermetic_root_bazel_workspace_dir)):
+                module_ctx.watch(path_to_track)
 
     paths_to_track_file = tag_path.get_child("paths_to_track.json")
     warnings_output_file = tag_path.get_child("warnings_output.json")

crate_universe/private/crates_repository.bzl

@@ -76,6 +76,8 @@ def _crates_repository_impl(repository_ctx):
         repin_instructions = repository_ctx.attr.repin_instructions,
     )
 
+    nonhermetic_root_bazel_workspace_dir = repository_ctx.workspace_root
+
     # If re-pinning is enabled, gather additional inputs for the generator
     kwargs = dict()
     if repin:
@@ -92,6 +94,11 @@ def _crates_repository_impl(repository_ctx):
             repository_name = repository_ctx.name,
         )
 
+        for path_to_track in splice_outputs.extra_paths_to_track:
+            # We can only watch paths in our workspace.
+            if path_to_track.startswith(str(nonhermetic_root_bazel_workspace_dir)):
+                repository_ctx.watch(path_to_track)
+
         kwargs.update({
             "metadata": splice_outputs.metadata,
         })
@@ -109,7 +116,7 @@ def _crates_repository_impl(repository_ctx):
         lockfile_path = lockfiles.bazel,
         cargo_lockfile_path = lockfiles.cargo,
         repository_dir = repository_ctx.path("."),
-        nonhermetic_root_bazel_workspace_dir = repository_ctx.workspace_root,
+        nonhermetic_root_bazel_workspace_dir = nonhermetic_root_bazel_workspace_dir,
         paths_to_track_file = paths_to_track_file,
         warnings_output_file = warnings_output_file,
         skip_cargo_lockfile_overwrite = repository_ctx.attr.skip_cargo_lockfile_overwrite,

crate_universe/private/splicing_utils.bzl

@@ -188,7 +188,14 @@ def splice_workspace_manifest(
     if not spliced_metadata.exists:
         fail("Metadata file does not exist: " + str(spliced_metadata))
 
+    extra_paths_to_track_path = repository_ctx.path(output_dir.get_child("extra_paths_to_track"))
+    if extra_paths_to_track_path.exists:
+        extra_paths_to_track = repository_ctx.read(extra_paths_to_track_path).split("\n")
+    else:
+        extra_paths_to_track = []
+
     return struct(
         metadata = spliced_metadata,
         cargo_lock = spliced_lockfile,
+        extra_paths_to_track = extra_paths_to_track,
     )

crate_universe/private/srcs.bzl

@@ -28,7 +28,6 @@ CARGO_BAZEL_SRCS = [
     Label("//crate_universe:src/metadata/cargo_tree_rustc_wrapper.sh"),
     Label("//crate_universe:src/metadata/dependency.rs"),
     Label("//crate_universe:src/metadata/metadata_annotation.rs"),
-    Label("//crate_universe:src/metadata/workspace_discoverer.rs"),
     Label("//crate_universe:src/rendering.rs"),
     Label("//crate_universe:src/rendering/template_engine.rs"),
     Label("//crate_universe:src/rendering/templates/module_bzl.j2"),

crate_universe/src/cli/splice.rs

@@ -5,13 +5,16 @@ use std::path::PathBuf;
 use anyhow::Context;
 use camino::Utf8PathBuf;
 use clap::Parser;
+use itertools::Itertools;
 
 use crate::cli::Result;
 use crate::config::Config;
 use crate::metadata::{
     write_metadata, Cargo, CargoUpdateRequest, Generator, MetadataGenerator, TreeResolver,
 };
-use crate::splicing::{generate_lockfile, Splicer, SplicingManifest, WorkspaceMetadata};
+use crate::splicing::{
+    generate_lockfile, Splicer, SplicingManifest, WorkspaceMetadata,
+};
 
 /// Command line options for the `splice` subcommand
 #[derive(Parser, Debug)]
@@ -80,14 +83,12 @@ pub fn splice(opt: SpliceOptions) -> Result<()> {
         }
     };
 
-    // Generate a splicer for creating a Cargo workspace manifest
-    let splicer = Splicer::new(splicing_dir, splicing_manifest)?;
-
     let cargo = Cargo::new(opt.cargo, opt.rustc.clone());
 
-    // Splice together the manifest
+    // Generate a splicer for creating a Cargo workspace manifest
+    let splicer = Splicer::new(splicing_dir.clone(), splicing_manifest)?;
     let manifest_path = splicer
-        .splice_workspace()
+        .splice()
         .with_context(|| format!("Failed to splice workspace {}", opt.repository_name))?;
 
     // Generate a lockfile
@@ -121,8 +122,8 @@ pub fn splice(opt: SpliceOptions) -> Result<()> {
 
     // Write metadata to the workspace for future reuse
     let (cargo_metadata, _) = Generator::new()
-        .with_cargo(cargo)
-        .with_rustc(opt.rustc)
+        .with_cargo(cargo.clone())
+        .with_rustc(opt.rustc.clone())
         .generate(manifest_path.as_path_buf())
         .context("Failed to generate cargo metadata")?;
 
@@ -147,5 +148,22 @@ pub fn splice(opt: SpliceOptions) -> Result<()> {
     std::fs::copy(cargo_lockfile_path, output_dir.join("Cargo.lock"))
         .context("Failed to copy lockfile")?;
 
+    if let Splicer::Workspace { path, .. } = splicer {
+        let metadata = cargo.metadata_command_with_options(
+            path.as_std_path(),
+            vec![String::from("--no-deps")],
+        )?.exec().with_context(|| {
+                format!(
+                    "Error spawning cargo in child process to compute crate paths for workspace '{}'",
+                    path
+                )
+            })?;
+        let contents = metadata
+            .packages
+            .iter()
+            .map(|package| package.manifest_path.clone())
+            .join("\n");
+        std::fs::write(opt.output_dir.join("extra_paths_to_track"), contents)?;
+    }
     Ok(())
 }

crate_universe/src/cli/vendor.rs

@@ -217,7 +217,7 @@ pub fn vendor(opt: VendorOptions) -> anyhow::Result<()> {
 
     // Splice together the manifest
     let manifest_path = splicer
-        .splice_workspace()
+        .splice()
         .context("Failed to splice workspace")?;
 
     // Gather a cargo lockfile

crate_universe/src/metadata.rs

@@ -4,7 +4,6 @@ mod cargo_bin;
 mod cargo_tree_resolver;
 mod dependency;
 mod metadata_annotation;
-mod workspace_discoverer;
 
 use std::env;
 use std::fs;
@@ -21,7 +20,6 @@ pub(crate) use self::cargo_bin::*;
 pub(crate) use self::cargo_tree_resolver::*;
 pub(crate) use self::dependency::*;
 pub(crate) use self::metadata_annotation::*;
-pub(crate) use self::workspace_discoverer::*;
 
 // TODO: This should also return a set of [crate-index::IndexConfig]s for packages in metadata.packages
 /// A Trait for generating metadata (`cargo metadata` output and a lock file) from a Cargo manifest.